1. Preheat oven to 375 degrees Fahrenheit. Grease and flour 8" x 12" pan.
2. Sift together the flour, baking powder, and salt. Set aside.
3. In a large bowl, cream together the margarine, sugar, and vanilla until light and fluffy. Add the egg replacer. Gradually add the flour mixture and soymilk, alternating.
4. Pour the batter into the pan and bake for 40 minutes. Let stand for 10 minutes, and then turn out onto a wire rack and cool completely. Store cake overnight in the fridge. This will make the cake easier to work with later.
5. For the icing, combine powdered sugar and cocoa powder. Heat soymilk and margarine together until the margarine is melted. Mix together to create an icing consistency. Cut the cake into 24 squares. Place coconut in a shallow container. Dip each square in the icing with a fork, and then roll them in the coconut. Place on a rack to dry.
Source of recipe: Modified/veganized from http://www.joyofbaking.com/Lamingtons.html